Frequency adjusting apparatus



May 23, 1933. L. A. GEBHARD El" AL 1,910,007

FREQUENCY ADJUSTING APPARATUS Filed April 18, 1950 s Sheets-Sheet 1 ATTORNEY 1933- L. -A. GEBHARD r-:r AL 1,910,007

FREQUENCY ADJUSTING APPARATUS Filed April 18, ,1930 5 Sheets-Sheet 2 swam Q0/1410 61. 945/2444), Pam vie l amofyfi,

ATTORNEY May 23, 1933. A. GEBHARD ET AL 1,910,007

FREQUENCY ADJUSTING APPARATUS Filed April l8J 1930 3 Sheets-Sheet 5 TTORNEY Patented May 23, 1933 UNlTED STATES PATE'r cries LOUIS A. GEBHARD AND CORRIE F. RUDOLPH, OF WASHENGTON, DESTR-ICT OF COLUMBIA; SAID GEBHARD ASSIGNOR TO WIRED RADIO, ENG, 611 NEW YGEK, N. 1.,

A CORPORATION OF DELAWARE FREQUENCY ADJUSTING APPARATUS Application filed April 18,

Our invention relates broadly to high frequency inductance systems and more particularly to a construction of high frequency inductance having means for automatically rendering effective additional impedance in the transmission circuit at predetermined adjustments within the range of the high frequency inductance system.

()ne of the objects of our invention is to provide a construction of high frequency inductance having adjustable means located adjacent the inductance and automatically operative to cut in or out of a transmission circuit additionalimpedance coordinated in value with the value of the selected inductance of the inductance system.

Another object of our invention is to provide an automatic switching system operative at a selected point along the high frequency inductance for automatically rendering effective or ineffective additional impedance in a transmitter circuit, the relative effective value of the inductance up to the point of automatic control of the additional impedance elements being readily selectable.

A further object of our invention is to provide a construction of a high frequency inductance wherein the inductance is spirally nounted along an insulated frame and the effective value of the inductance in a signaling circuit controlled by moving a contact member along the inductance with means auxiliary to the inductance and operative by the movement of the contact member to a selected position for tripping auxiliary 1930. Serial N0. 445,413

of the inductance system of our invention; Fig. 2 is a lateral cross-sectional view through the inductance system on line 2-2 of Fig. 1; Fig. 3 is a detailed cross-sectional view taken through the contact device and the automatic actuator which is selectively controlled thereby for rendering auxiliary impedance elements effective or ineffective with respect to the variable inductance; Fi 4 is an end elevation of the inductance system illustrated in Fig. 1; Fig. 5 is an enlarged elevational view partiall in sect n of the switching device which is operate by the actuator which is in turn controlled by the contact member which selects the effective inductance in the high frequency system; and Fig. 6 is acrosssectional view through the switching dev'ce on line 66 of Fig. 5.

In a high frequency transmitter employing screen grid tubes and covering a wide frequency band, the output circuits of the screen grid tubes are normally tuned by the use of a continuously variable inductance coil. If the frequency band covered by the continuously variable adjustment is insuilicient', it is necessary to connect a condenser in parallel with the coil at some point in the range of adjustment. It is also desirable when changing from singling to doubling operation in the amplifier stage to change the grid potential at the same time.

The inductance system of our invention is constructed with an automatic actuator pro jected in the path of the variable contactor which moves over the high frequency inductance. The actuator is arranged to trip a switching device which connects a condenser in parallel with the inductance for fixing the frequency range thereof for the desired transmitter operation. The position of the actuator with respect to the path of the contactor along the inductance is variable and the actuator may be set at selected positions for cutting in the auxiliary capacity at predetermined times along the path of the contactor within the inductance. he construction of our invention will be more clearly understood by detailed reference to the drawings.

Referring to the drawings, reference character l designates the inductance which is formed by a fiat spiral strip helically positioned concentrically within a plurality of longitudinally extending insulated bars 2, 3, 4, 5, 6 and 7. The insulated bars 27 are supported at opposite ends in the frame structure of the inductance system in end members 8 and 9 by suitable securing means such as screw devices 2a, 3a, 4a, 5a, 6a, and 7a. A fixed shaft 10 is secured in the end member 8 and is provided with suitable screw threads 11 cut thereon in spiral formation. A tubular member 60 encloses shaft 10 and is rotatable under control of crank 36 from the end 9 of the frame. The tubular member 60 is slotted at 61 to admit the pin 12 therethrough, which pin also extends through the sleeve 13 of a longitudinally movable slider. The longitudinally movable slider 13 carries an extension 14 at one side thereof roviding a support for a pair of resilient rush members 30 which are formed in jaws and engage opposite sides of the strip 1. Suitable attachment means such as screws 31 are employed to secure the resilient brushes 30 to the extension 14. In order to protect the resilient brush members 30, we rovidc a pair of rigid plate members 32 an 33 which are secured to opposite sides of the extension 14 by screws 34 and 35, respectively. The rigid plate members 32 and 33 are cut in the form of yokes indicated more clearly at 32a and 33a in such manner that portions of the yokes extend over the strip 1 for a distance substantially equal to one-half the width of the strip 1 Or for a distance which is equal to the portion of strip 1 which projects from the insulated bars 2 7. The yokes 32a and 3311 enable the rigid members 32 and 33 to pass freely between the spaced turns of inductance 1 in the course of the rotation of control shaft 10. The sleeve 60 is operated by means of a suitable crank 36 from one end of the inductance system which drives crank 36. and the gear 37 which is associated therewith. The gear 37 meshes with bevel gear 38 for driving the tachometer 39 enabling the slider 13 to be moved to predetermined positions along the length of the inductance 1 and set in such position. In order that all lost motion which may occur in the movable slider 13 may be eliminated, we provide a split tubular extension 40 on the slider 13 which frictionally engages with the surface of tubular member 60 enablin the slider to be set in a selected position. The frame including the end members 8 and 9 is suitably supported on brackets 41 and 42 from the transmitter frame which we have designated generally at 43. At opposite ends of the frame structure on end members 8 and 9 we secure bracket members 44 and 45 in which there is j ournaled the longitudin ally extending rockable shaft 46. The shaft 46 extends through an auxiliary frame 47 on the end of the frame of the inductance system and there controls the operation of a switching system as will be more fully described hereinafter. The switching system includes the depending rockable blade 19 which carries a pair of resilient brush portions 20 to engage opposite faces of fixed contacts 21 and 22. The blade 19 is carried by shaft 46 under a condition of spring tension. The spring tension mounting of blade 19 is obtained by the assembly of the oppositely directed sets of pins 17 and 18 carried by plate member 25 which is secured to shaft 46 and the sets of pins 26 and 27 which project from the pivoted end portion of blade 19. A spring 16 having projecting ends thereon is coiled between the sets of pins 17-18 and 26-27 forming a resilient interlock between the rockableshaft 46 and the switch blade 19.

The switch blade 19 is free to move with respect to the portion 46a of the shaft 46 and is controlled in its movement thereover by the tension of coil sprin 16. Washer members 23 and 28 are carrie by the reduced portion 46a of rockable shaft 46 on each side of the supporting member 24 of the auxiliary frame 47. The securing means 29 serves to center the rockable shaft 46 in the frame structure of the inductance system free for angular movement by reason of the lost motion 0btainable under the action of the washer members 23 and 28. The auxiliary frame 47 consists of a multiplicity of spacer members 48 interconnecting the plate members 44 and 24. In order to actuate therockable shaft 46, an adjustable actuator 50- may be selec tively positioned along shaft 46 at any desired point to be engaged b the movable contactor for imparting a roc ing movement to shaft 46 at a predetermined distance along the inductance from the end thereof. The actuator 50 is provided with a set screw 51 therein which projects into a longitudinally extending groove 46?) in shaft 46. By backing off-on set screw 51 the actuator may be shifted at any desired position along shaft 46. The actuator is in the form of a yoke having a air of arms designated at 52, each of which has a curvilinear face 9 embracing opposite sides of a turn of the inductance 1. That is to say, the actuator 50 is so shaped that the arms 52 thereof extend between adjacent turns of inductance 1. By backing off on set screw 51 the actuator 50 may be moved in an orbit which we have designated at 53 in Fig. 2 and the curvilinear faces 9 of actuator 50 presenting in a path forming an abutment for the movement of the contactor along in ductance 1. That is to say, the extensions 326; or 33a are brought into abutment with the curvilinear faces of the arms 52 of the actuator 50. Continued movement of crank 36 results in the imparting of a twisting torque to actuator 50 resulting in the rocking of shaft 46 and the throw of switch 19 which is moved from one contact position to another. Spring 16 insures the quick throw of switch blade 19 and takes up any lost motion therein. Suitable stops 21a and'22a limit the movement of switch blade 19 in either direction. As the contactor strikes the actuator in a clockwise approach along the inductance l in Fig. 1, the actuator 50 is thrown to the dotted line position illustrated in Fig. 2 resulting in the throwing of switch 19 to contact 21. As the slider 14: is returned in a counter-clockwise direction, the actuator 50 is thrown to the full line position moving the switch blade 19 to'full line position on contact 22. That is to say, the contactor is free to pass the actuator in either direction by virtue of the curvilinear faces 9 and in the course of that passage an actuating movement may be imparted to the switch 19. Suitable circuit connections extend from contacts 21 and 22 for the connection of a condenser or other impedance element in the circuit including the inductance 1. A condenser may be connected in parallel with the coil 1 at any point along the length of the inductance l at which time the actuator is set. Various circuit arrangements may be employed including the inductance and the associated impedances may be cut in at any desired time during the course of movement of the sliding contactor.

The apparatus of our invention is particularly efiicient in operation in short wave transmitters where the number of controls must be a minimum and where quick change from one frequency to another frequency over a relatively wide frequency band is required.

We have illustrated but one auxiliary shaft 46 extending parallel to the inductance 1. It will be understood, however, that a number of auxiliary shafts and operatively related switches may be employed and that separate actuators may be mounted upon such auxiliary shafts so that a multiplicity of diiierent circuits may be independently controlled according to the movable contactor along the inductance. It, will be understood that the movable contactor is free to pass beneath the actuator after effecting an operation thereof so that any number of additional turns of the inductance may be inserted in the circuit.

While we have described a preferred embodiment of'our invention, we desire that it be understood that modifications may be made and that no limitations upon our invention are intended other than are imposed by the scope of the appended claims.

What we claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A high frequency inductance system comprising a continuously variable inductance including a moving contactor variable to different positions longitudinally along the interior of said inductance, a switching mechanism, an actuator for controlling the operation of said switching mechanism, said actuator extending between the turns of said inductance and movable in a plane normal to the axis of the inductance and in the path of the movable contactor for operating said switching mechanism in accordance with the position of said movable contactor along said inductance.

2. In a high frequency inductance system, a frame structure, an inductance helically wound on said frame structure, a shaft extending through said inductance, a movable contactor operated by said shaft and movable radially within said inductance to selected positions along said inductance, a switching system, an actuator for controlling the movement of said switching system to either of two positions, said actuator extending between the turns of said inductance at a selected position along the length thereof in a plane normal to t 1e axis of said inductance and providing an abutment for said movable contactor for shi tng said switching system to either of the limiting positions thereof.

3. A high frequency inductance system comprising a frame structure, a helical inductance supported on said frame structure, a rotary shaft member extending through said frame structure, a contactor movable along said rotary shaft in a clockwise or counter-clockwise direction for selecting the effective number of turns of said inductance, a switch member movable to either of two limiting positions, an actuator for controlling the operation of said switcn member, said actuator extending between the turns of said in ductance and providing an abutment for said movable contactor for shiftingsaid switch member to either of said movable positions in accordance with the clockwise or counterclockwise direction of movement of said movable contactor with respect to said actuator.

4. In a high frequency inductance system, a helical inductance, a contactor movable radially within said inductance to various posi tions along said inductance, a switching mechanism, and means for actuating said switching mechanism in timed relation to the movement of said movable contactor to a predetermined position along said inductance, said means comprising a rockable actuator mounted adjacent said inductance and rockable into and out of the of said contactor interiorly of said inductance.

5. In a high frequency inductance system, an inductance, a contactor adjustable interiorly of said inductance for varying the effective number of turn in said inductance, a switching mechanism for controlling the connection of an impedance in circuit with a predetermined amount of said inductance, and means pivotally mounted in a plane normal to the axis of said inductance and actuated by the movement of said contactor for selectively actuating said switching mechanism when a predetermined amount of said inductance is rendered effective or ineffective, said means comprising a rockable actuator mounted adjacent said inductance and rockable into and out of the path of said'contactor interiorly of said inductance.

6. In a high frequency inductance system, a frame structure, an inductance carried by said frame structure, a movable contact member engaging the interior of the turns of said inductance, means for rotatably shifting said movable contact member to various positions along said inductance, a switching mechanism movable to either of two limitin positions for connecting an auxiliary impe ance in circuit with selected amounts of said inductance, and means controlled by the movement of said contactor for actuating said switchin mechanism, said means comprising a roc able actuator mounted adjacent said inductance and rockable into and out of the ath of said contactor in a plane normal to t e axis of said inductance.

7. In a high frequency inductance system, a frame structure, an inductance mounted on said frame structure, a movable contactor for varying the effective value of said inductance, a switching mechanism for controlling the connection of an impedance in circuit with a selected portion of said inductance, a rod member extending longitudinally of said inductance, and an actuator adjustable on said rod member to various positions along said inductance and projecting into the path of said movable contactor for shifting said switching mechanism to either of two limiting positions simultaueously with the ositioning of said movable contactor at a se ected point along said inductance.

8. A high frequency inductance system comprising a frame structure, an inductance carried by said frame structure, a movable contactor rotatable within said inductance and variable in position along said inductance, a rod member extending longitudinally of said inductance, a switching system connected with said rod member and movable to either of two limiting positions, a rockable actuator connected with said rod member, said rockable actuator projecting in the path of said movable contactor and operative by the abutment of said movable contactor therewith for imparting angular movement to said rod member and correspondingly shifting said switching system to either of said limiting positions.

9. In a high frequency inductance system, a frame structure, an inductance carried by said frame structure, a contactor angularly movable within sa d inductance and variable in position along said inductance, a switching system movable to either of two limiting posit ons, a rod member connected with said switching system and extending longitudinally of said inductance, an em.

ator carried by said rod member, said actu ator having the form of a yoke embracin a turn of said inductance and extending in t path of said movable contactor in a lane normal to the axis of said inductance an providing an abutment therefor for shifting said switching system to either of said limiting positions in a direction corresponding to the direction of rotation of said contactor.

10. In a high frequency inductance system, a frame structure, an inductance carried thereby, a contactor variable in position along said inductance, said contactor embracing opposite sides of each turn of said inductance, a switching system movable to either of two limiting positions, an actuator for controlling the operation of said switching system, said actuator comprising a yoke projectible between the turns of said inductance at a selected position along the length thereof and providing an abutment for the protruding portions of said contactor extending between the turns of the inductance for moving said switching system to either of the two limiting positions thereof according to the direction of rotation of said contactor.

11. A high frequency inductance systemcomprising a frame structure, a helical inductance supported by said frame structure, a variable contactor movable to selected positions along said inductance, a rockable shaft member journaled adjacent said frame structure, a switching mechanismmovable to either of two limiting positions and controlled by the rocking movement of said shaft member, an actuator carried by said shaft member and extending between the turns of said inductance at any selected point along the length thereof, said actuator extending in the path of said movable contactor whereby abutment of said movable contactor with said actuator operates to shift said switching mechanism to either of the two limiting positions thereof.

12. In a high frequency inductance system, a frame structure, an inductance earned by said frame structure, a contactor movable along said inductance, said contactor comprising a pair of brush members resiliently engaging opposite sides of each turn of said inductance, yoked guide members embracing each turn of said inductance and carried by said contactor, a switching system movable to either of two limiting positions, a rockable shaft member connected with said switching system, an actuator carried by said movable shaft member, said actuator including a yoke extensible on opposite sides of a selected turn of said inductances with curvilinear faces formed on the ends of said yoke and projectible in the path of said movable contactor for shifting said switching mechanism to either of two limiting positions according to the direction of movement of said contactor with respect to the curvilinear faces of said actuator.

13. In a high frequency inductance system, a frame structure, an inductance carried by said frame structure, a contaotor variable in position along said inductance, said contactor including a pair of brushes engaging opposite sides of each turn of said inductance, yoke members adjacent said brushes and carried by said movable contactor, said yoke members extending on opposite sides of each turn of said inductance, a shaft member positioned adjacent said frame structure, an actuator movable to selected positions along said shaft member and projectible between adjacent turns of said inductance, a switchingmechanism controlled by said shaft member and movable to either of two limiting positions, said actuator having yoked eX- tensions embracing opposite sides of the selected turn of said inductance projecting in the path of the yoke members on said movable contactor whereby said movable contactor abuts With said actuator While shifting said switching mechanism to either of the tWo limiting positions thereof.

LOUIS A. GEBHARD. CORRIE F. RUDOLPH. 

